Substrate table, a lithographic apparatus and a device manufacturing method

Abstract

A table for a lithographic apparatus, the table having a catchment opening formed in an upper surface of the table, the catchment opening in fluid communication through the table with the environment of the table at a drain opening in a surface of the table other than the upper surface.

The invention claimed is: 
     
       1. A table for a lithographic apparatus, the table comprising:
 a supporting area on which an object is to be supported; 
 an outlet opening; 
 a catchment opening at an upper portion of the table and located below the supporting area, the catchment opening in fluid communication with the outlet opening and the catchment opening having a cross-section extending in a direction with a horizontal component; 
 a porous structure in a flow path between the catchment opening and the outlet opening; and 
 a liquidphobic surface, below the supporting area, adjoining the catchment opening and configured to guide liquid to the porous structure, the guiding liquidphobic surface at least partly extending in a direction with a horizontal component and arranged to receive liquid at first portion of the guiding liquidphobic surface and have at least part of the porous structure located at a second portion of the guiding liquidphobic surface, the second portion displaced in a horizontal direction from the first portion. 
 
     
     
       2. The table of  claim 1 , wherein the liquidphobic surface extends around the catchment opening. 
     
     
       3. The table of  claim 1 , wherein the porous structure is configured to stop liquid flow and accumulate liquid above the porous structure. 
     
     
       4. The table of  claim 1 , further comprising a chamber in the flow path, the chamber having the catchment opening at an upper end thereof and the outlet opening at a lower end thereof, wherein at least part of the chamber is wider than the catchment opening. 
     
     
       5. The table of  claim 1 , wherein the flow path further comprises a collector portion below the porous structure and above a substantially vertical or horizontal portion of a channel arrangement fluidly connecting the porous structure and a drain opening. 
     
     
       6. The table of  claim 1 , comprising a further porous structure in the flow path between the catchment opening and the porous structure. 
     
     
       7. The table of  claim 1 , further comprising a channel arrangement fluidly connecting the porous structure and a drain opening, the channel arrangement comprising a first substantially vertical portion located below at least part of the porous structure, a substantially horizontally extending portion connected to the first substantially vertical portion and located below the first substantially vertical portion, and a second substantially vertical portion extending downward from the substantially horizontally extending portion. 
     
     
       8. The table of  claim 1 , wherein the object is a semiconductor substrate and and wherein the catchment opening is outward of the supporting area. 
     
     
       9. The table of  claim 1 , wherein the catchment opening is in fluid communication with the environment of the table at a location downstream from the porous structure. 
     
     
       10. A lithographic apparatus, comprising:
 a projection system configured to project a beam of radiation through a liquid onto a substrate; 
 a liquid supply system configured to supply a liquid to a region between the projection system and the substrate; 
 a table comprising:
 a supporting area on which an object is to be supported, 
 an outlet opening, 
 a catchment opening at an upper portion of the table and located below the supporting area, the catchment opening in fluid communication with the outlet opening and the catchment opening having a cross-section extending in a direction with a horizontal component, 
 a porous structure in a flow path between the catchment opening and the outlet opening, and 
 a liquidphobic surface adjoining the catchment opening and configured to guide liquid to the porous structure, the guiding liquidphobic surface at least partly extending in a direction with a horizontal component and arranged to receive liquid at first portion of the guiding liquidphobic surface and have at least part of the porous structure located at a second portion of the guiding liquidphobic surface, the second portion displaced in a horizontal direction from the first portion. 
 
 
     
     
       11. The apparatus of  claim 10 , wherein the liquidphobic surface extends around the catchment opening. 
     
     
       12. The apparatus of  claim 10 , wherein the porous structure is configured to stop liquid flow and accumulate liquid above the porous structure. 
     
     
       13. The apparatus of  claim 10 , further comprising a chamber in the flow path, the chamber having the catchment opening at an upper end thereof and the outlet opening at a lower end thereof, wherein at least part of the chamber is wider than the catchment opening. 
     
     
       14. The apparatus of  claim 10 , wherein the flow path further comprises a collector portion below the porous structure and above a substantially vertical or horizontal portion of a channel arrangement fluidly connecting the porous structure and a drain opening. 
     
     
       15. The apparatus of  claim 10 , comprising a further porous structure in the flow path between the catchment opening and the porous structure. 
     
     
       16. The apparatus of  claim 10 , further comprising a channel arrangement fluidly connecting the porous structure and a drain opening, the channel arrangement comprising a first substantially vertical portion located below at least part of the porous structure, a substantially horizontally extending portion connected to the first substantially vertical portion and located below the first substantially vertical portion, and a second substantially vertical portion extending downward from the substantially horizontally extending portion. 
     
     
       17. The apparatus of  claim 10 , wherein the object is a semiconductor substrate and the catchment opening is outward of the substrate supporting area. 
     
     
       18. A table for a lithographic apparatus, the table comprising:
 a plurality of protrusions extending from the table, the ends of the protrusions defining a support plane configured to support an object; 
 a catchment opening at an upper portion of the table, the catchment opening located below the support plane, the catchment opening in fluid communication with an outlet opening, and the catchment opening having a cross-section extending in a direction with a horizontal component; 
 a chamber in a flow path between the catchment opening and the outlet opening, the chamber configured to collect immersion liquid and the chamber having the catchment opening at an upper end thereof and the outlet opening at a lower end thereof, wherein at least part of the chamber is wider than the catchment opening; 
 a first porous structure located in the flow path and below the catchment opening; 
 a second porous structure, located above the first porous structure, configured to receive immersion liquid from the catchment opening; and 
 a liquidphobic surface adjoining the catchment opening and configured to guide liquid to the second porous structure, the guiding liquidphobic surface at least partly extending in a direction with a horizontal component and arranged to receive liquid at first portion of the guiding liquidphobic surface and have at least part of the porous structure located at a second portion of the guiding liquidphobic surface, the second portion displaced in a horizontal direction from the first portion. 
 
     
     
       19. The table of  claim 18 , wherein the first porous structure is configured to stop liquid flow and accumulate liquid above the first porous structure in the chamber. 
     
     
       20. A lithographic apparatus, comprising a projection system configured to project a beam of radiation through a liquid onto a substrate, a liquid supply system configured to supply a liquid to a region between the projection system and the substrate, and the table according to  claim 18 .